IDF International Dragonfly Fund Report Journal of the International Dragonfly Fund 1­15 Vincent J. Kalkman & Thinley Gyeltshen Records of dragonflies from western Bhutan collected in October 2015 Published 12.04.2016 94 ISSN 1435­3393 The International Dragonfly Fund (IDF) is a scientific society founded in 1996 for the impro­ vement of odonatological knowledge and the protection of species. Internet: http://www.dragonflyfund.org/ This series intends to publish studies promoted by IDF and to facilitate cost­efficient and ra­ pid dissemination of odonatological data.. Editorial Work: Martin Schorr Layout: Martin Schorr IDF­home page: Holger Hunger Indexed: Zoological Record, Thomson Reuters, UK Printing: Colour Connection GmbH, Frankfurt Impressum: Publisher: International Dragonfly Fund e.V., Schulstr. 7B, 54314 Zerf, Germany. E­mail: [email protected] Responsible editor: Martin Schorr Cover picture: Aristocypha cuneata ♀ Photographer: Prosenjit Dawn: http://www.indianodonata.org/media_images/ 2016/28_628­112­559807f7d1bab­1.jpg Published 12.04.2016 Records of dragonflies from western Bhutan collected in October 2015 Vincent J. Kalkman1 & Thinley Gyeltshen2 1Naturalis Biodiversity Center, P.O. Box 9517, 2300 RA Leiden, The Netherlands E­mail: [email protected] 2School of Life Sciences, Sherubtse College, Kanglung, Bhutan E­mail: [email protected] Abstract Distribution data of dragonflies and damselflies from western Bhutan collected during a trip from 10 October 2015 to 22 October 2015 are presented. In total 53 species were recorded of which eleven are new to the country (Aciagrion palli­ dum, Anisopleura lestoides, Megalestes irma, Gynacantha incisura, Gynacantha khasiaca, Gynacanthaeschna sikkima, Lamelligomphus risi, Somatochlora daviesi, Crocothemis erythraea, Sympetrum fonscolombii, Tholymis tillarga). Another three species, one Megalestes and two Cephalaeschna, were not identified to species level but are also addition to the list of species recorded from Bhutan. Key words: Odonata, faunistics, taxonomy, Bhutan Introduction Bhutan is a relatively small country in the eastern Himalayas. The kingdom of Bhutan is dominated by mountains intersected by often narrow valleys. Most parts of Bhutan lie at high elevation and most of its main towns are found at higher altitude with the capital Thimphu at 2.200­2.700 m. a.s.l. and Paro at 2.200 m a.s.l. Due to its strong gradient most of its land surface is still covered by natural vegetation and the country boost large areas with natural forest. Access to many of the areas is how­ ever difficult due to lack of road connections. The lower parts of Bhutan reach down to 200 meters were the mountains of Bhutan abruptly end and the plains of India begin. These areas are hot and humid and are strongly impacted by the Monsoon rains which run from June to August. The fauna in the region below 1000 meters is IDF­Report 94 | 1 Kalkman & Gyeltshen probably the most species rich as many typical and often widespread Oriental spe­ cies can be found. A checklist and bibliography of the dragonflies and damselflies of Bhutan is in pre­ paration (Gyeltshen et al. 2016). Only 12 papers containing original data on Bhutan have been published the first dating back to 1936 (Fraser 1936) and with the second only appearing in 1977 (Lieftinck 1977). The odonate fauna of Bhutan is still incom­ pletely documented although good progress has been made during the last deca­ de mainly by the work of Amit Mitra. Information on habitat, flight period and distri­ bution within the country are scarce. Currently around 100 species are known from Bhutan but it seems likely that close to 150 species occur in the country. In this paper the results of field work conducted in October 2015 are presented. Material and Methods Field work was conducted from 10 October 2015 to 22 October 2015 by Vincent Kalk­ man and Thinley Gyeltshen. During this period the following districts in Bhutan were visited: Chukha, Tsirang, Gasa, Sarpang, Paro, Shemgang, Thimphu, Tongsa, Wang­ di Phodrang (Figure 1­4). Large parts of Bhutan are difficult to access and field work was conducted by driving along the roads connecting villages and stopping at suitable sites. In most cases the roads follows the course of the main rivers. These rivers are large, have a high current and run over a bed of stones and boulders with stretches of sand or detritus being near absent (Figure 5). Dragonflies are largely lack­ ing in these rivers although at sparse places small standing pools are suitable for re­ production, a situation probably mostly occurring during late summer when the water table is low. In most cases suitable habitats consist of smaller brooks running towards Figure 1. Localities sampled between 10 October 2015 to 22 October 2015. 2 | IDF­Report 94 Western Bhutan Odonata collected in October 2015 Figure 2. Sampling localities, eastern section. Figure 3. Sampling localities, northwestern section. the main rivers (Figure 6 & 7). Such smaller brooks are surprisingly scarce in some re­ gions. Many of the brooks visited were steep and were often only accessible for a short stretch with the brook on one side of the road being too steep to climb and on the other side plunging down into the valley. Only at site 27 a larger brook with a less steep gradient holding stretches of sand and detritus could be sampled (Figure 8). Some of the brooks we sampled in the lowland close to India strongly suffered from IDF­Report 94 | 3 Kalkman & Gyeltshen human impact (Figure 9) although undoubtedly many good streams are still present slightly away from human habitation. Stagnant waters are rare. Larger natural stand­ ing waters were only visited at site 26 (Figure 10) and 42, although at the later the weather conditions were poor for field work. Artificial standing waters included ponds at Lamperi Royal Botanical Park (site 3), a pond at a university complex (site 43) and fishponds at site 11 and 29. A large portion of the cultivated lands are in use as rice paddies but these are largely dry in autumn. Figure 4. Sampling localities, southwestern section Figure 5. Many of the larger rivers in Bhutan have a strong current, cold water and lack sections with sand or detritus rendering them poor in dragonflies. Confluence of the Phu Chu and Mo Chu at Punakha Dzong. 4 | IDF­Report 94 Western Bhutan Odonata collected in October 2015 Figure 6. Brook at location 2 (20151010B). At this site Cephalaeschna triadica, Ce­ phalaeschna spec A, Cephalaeschna spec B. Indolestes cyaneus and Sympetrum hypomelas were found. Figure 7. Brook at location 13 (20151012D). At this site Anisopleura lestoides, Calicne­ mia eximia, Ceriagrion fallax, Gynacantha incisura, Gynacanthaeschna sikkima, Mega­ lestes irma, Orthetrum glaucum and O. glaucum were found. Figure 8. Brook at location 27 (20151015A) the only larger brook with a less steep gradient holding stretches of sand and detritus encountered. The following species were found: Anisogomphus spec., Calicnemia eximia, Macromia moorei, Neuro­ basis chinensis, Lamelligomphus risi, Orthetrum glaucum, O. pruinosum, O. triangulare, Pantala flavescens, Pseudagrion rubriceps, Trithemis aurora and T. festiva. IDF­Report 94 | 5 Kalkman & Gyeltshen Figure 9. Location 45 (20151021C). Many brooks and streams in the lowland were found to be strongly impacted by humans and their dragonfly fauna was strongly dominated by common and widespread oriental species. At this location the fol­ lowing species were found: Agriocnemis pygmaea, Argiocnemis rubescens, Ceri­ agrion coromandelianum, Crocothemis servilia, Neurobasis chinensis, Orthetrum glaucum, O. sabina, Pantala flavescens, Paragomphus lineatus, Pseudagrion rubri­ ceps, Tramea spec., Trithemis aurora and T. festiva. Figure 10. Natural standing waters are rare in Bhutan. At this small natural lake at 2042 m (location 26, 20151014G) the following species were found: Aeshna peta­ lura, Ceriagrion fallax, Indolestes cyaneus and Sympetrum hypomelas. 6 | IDF­Report 94 Western Bhutan Odonata collected in October 2015 The collected material will be stored in National Biodiversity Centre, Bhutan. Part of the material will be used for molecular work at the Naturalis Biodiversity Center (RMNH). All records were uploaded to Observado.org. Sampling localities All sampling localities are within Bhutan; the coordinates are in decimal degrees. 1. 20151010A, Paro District, Shapa, standing water on shingle along river, (27,3516, 89,4636): 10­10­2015 2. 20151010B, Thimphu District, Mewang, small steep brook, partly shaded, (27,3381, 89,5756): 10­10­2015 3. 20151011A, Thimphu District, Lamperi Royal Botanical Park, ponds at botanical garden, (27,5115, 89,7474; 2685m a.s.l.): 11­10­2015 4. 20151011B, Wangdi Phodrang District, Gase Tsho Aom, restaurant, (27,3374, 89,9239): 11­10­2015 5. 20151011C, Wangdi Phodrang District, Daga, degraded stream near road, (27,2381, 90,0495; 741m a.s.l.): 11­10­2015 6. 20151011D, Wangdi Phodrang District, Daga, steep brook, (27,2381, 90,0495; 741m a.s.l.): 11­10­2015 7. 20151011E, Wangdi Phodrang District, Daga, steep brook, (27,2110, 90,0510): 11­10­2015 8. 20151011F, Wangdi Phodrang District, Daga, rice paddy, (27,1283, 90,0718): 11­ 10­2015 9. 20151011F, Wangdi Phodrang District, Daga, rice paddy, (27,1283, 90,0718): 11­ 10­2015 10. 20151012A, Tsirang District, Tshokhana, large brook (to early in the morning), (27,0048, 90,1006; 1100m a.s.l.): 12­10­2015 11. 20151012B, Tsirang District, Goseling, fishpond, (27,0221, 90,1232): 12­10­2015 12. 20151012C, Tsirang District, Kikhorthang, small brook in largely open area, (27,0198, 90,1253; 1400m a.s.l.): 12­10­2015 13. 20151012D, Tsirang District, Kikhorthang, large steep brook with large boulders, (27,0071, 90,1423): 12­10­2015 14. 20151013A, Tsirang District, Beteni, brook in forest, (26,9664, 90,1493): 13­10­2015 15. 20151013B, Sarpang District, Hile, Large stony brook in largely cultivated area, (26,9090, 90,2206): 13­10­2015 16. 20151013C, Sarpang District, Sarpangtrar, large stony brook in degraded forest, (26,8687, 90,2689): 13­10­2015 17.